Synthesis of an eco-inspired anticorrosive composite for mild steel applications.

We synthesised a polyaniline/mica (Mica-PANI) nanocomposite using naturally occurring muscovite mica by a top-down approach. The developed coating materials were characterised using a different technique to investigate their chemical and structural properties using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA). Furthermore, the electrochemical properties of the coating materials were investigated by linear sweep voltammetry (LSV). SEM images elucidate the composite's average particle diameter of the prepared nano-mica, approximately 80 nm. The existence of relevant functional groups and bonding in the prepared Mica-PANI composite material was confirmed by means of XPS and FTIR techniques. Moreover, the synthesised composite with 5% w/w shows high anticorrosion protection, i.e. 84 µm per year, compared to competing materials, including commercial paint and individual raw materials (0.35 mm per year). The anti-corrosive effect occurs mainly due to two opposing effects: the formation of an Fe(OH)3 passive layer on the steel surface by oxidation of surface iron atoms by the PANI and the barrier effect of mica NPs through inhibition of corrosive agents. Therefore, the eco-inspired composite could be an ideal cost-effective coating material to prevent the corrosion of mild steel surfaces.

Isolation of heavy metal-resistant Staphylococcus epidermidis strain TWSL_22 and evaluation of heavy metal bioremediation potential of recombinant E. coli cloned with isolated cadD.

A heavy metal-resistant bacterial strain, TWSL_22 was isolated from an industrial effluent sample and tested for heavy metal tolerance and resistance. The strain was molecularly characterized as Staphylococcus epidermidis based on 16S rDNA gene analysis and the sequence was deposited in the NCBI repository (accession number KT184893.1). Metal removal activity (P < .001) of TWSL_22 was 99.99 ± 0.001%, 74.43 ± 2.51%, and 51.16 ± 4.17% for Cd, Pb, and Cu, respectively. Highest MIC was observed for Cd. Antibiotic susceptibility assays revealed the strain TWSL_22 to be resistant to several antibiotics. The strain was screened for possible heavy metal-resistant genes and presence of cadA, copA, and cadD was confirmed by PCR. A DNA fragment containing complete sequence of cadD (618 bp) was isolated and cloned into pET 21a(+), transformed into E. coli BL21 and designated as E. coli/cadDET. E. coli/cadDET showed high metal tolerance capacity and could remove over 82% of heavy metals (Zn2+, Cd2+, Cu2+, and Cr3+) in the industrial effluent.

Assessment of the awareness of radiation protection and related concepts among nursing staff mainly working in diagnostic imaging units, cath-labs and operation theatres in Sri Lanka: A survey-based study.

INTRODUCTION: This study was carried out to evaluate the awareness of radiation protection, radiation types, medical imaging equipment and radiation effects among nurses for the first time in Sri Lanka. Since nurses are involved as direct caregivers in diagnostic and therapeutic radiography and radiation treatment procedures, they need to have a good understanding of the areas mentioned above. METHODS: A self-administered questionnaire was used to collect data from 391 nurses working in hospitals, clinics, and other healthcare settings. Forwarded questions gathered the participants' demographic details and assessed their awareness of radiation protection, medical imaging equipment, radiation type and radiation effects. The average score per awareness area for each demographic characteristic was calculated based on the responses. Additionally, the percentage of participants who scored above 50 and 75 was calculated for each awareness area. RESULTS: The majority were female participants (81.1%) and possessed a diploma in nursing (66.0%) with 10.8 years of average work experience. 92.3%, 74.7%, 69.8% and 22.3% of the participants scored more than 50 marks for the questions related to radiation protection, medical imaging equipment, radiation type and radiation effects, respectively. The level of nursing education and prior training in radiation protection significantly influenced all awareness areas, whereas participants with a graduate qualification in nursing and with prior radiation protection training scored the highest average marks. CONCLUSION: Based on the scores obtained, the Sri Lankan nurses have satisfactory awareness of the essential concepts related to radiation types, medical imaging equipment and radiation protection. However, there is a significant lacking of awareness of radiation effects. This can be attributed to the fact that most participants did not have any formal training in radiation protection. The results implicate that proper training in radiation protection can significantly influence awareness of radiation protection and related concepts. Therefore, it is a timely requirement to initiate short awareness programs and continuing education programs on radiation protection for nurses working in specialised radiation units. IMPLICATIONS FOR PRACTICE: The study suggests the necessity of initiating continuous education programs for nursing staff radiation protection to overcome the awareness gaps.

Albumin grafted coaxial electrosparyed polycaprolactone-zinc oxide nanoparticle for sustained release and activity enhanced antibacterial drug delivery.

One of the most serious issues faced by the healthcare sector is the development of multidrug resistance among various pathogens. It is such that developing new and more capable drugs takes far too long to counter such resistance. In order to overcome these concerns, this study focused on improving upon the coaxial electrospraying process by producing cloxacillin loaded albumin polycaprolactone (PCL) with a ZnO coating for sustained and activity enhanced drug delivery. Albumin-grafted, polycaprolactone-coated, zinc oxide-loaded cloxacillin (APCL-CLOX-ZnO) nanoparticles with a diameter of 85-110 nm were obtained via a coaxial electrospray technique. The encapsulation efficiency of cloxacillin of ZnO-CLOX was found to be approximately 60%. The loading efficiencies of ZnO-CLOX and APCL-CLOX-ZnO were found to be 40% and 28% respectively. Albumin was employed in order to impart immune evasion properties to the formulation. Drug-loaded ZnO NPs were analyzed using SEM, TEM, FT-IR and TGA. This novel formulation was shown to possess sustained release characteristics owing to the PCL and albumin coatings, relative to uncoated counterparts. ZnO-CLOX and APCL-CLOX-ZnO exhibited 72% and 52% cloxacillin release within 24 h. APCL-CLOX-ZnO exhibited potent antimicrobial activity against S. epidermidis, B. cereus and P. aeruginosa and some activity against E. coli with inhibition zones 32 ± 1.4, 34 ± 0.3, 32 ± 0.6 and 11 ± 0.4 mm, respectively. Cytotoxicity studies against murine preosteoblast cells revealed that the albumin-PCL coating served to drastically reduce initial toxicity against healthy mammalian cells. In vitro lung deposition study showed 70% of APCL-CLOX-ZnO particles can reach up to the alveoli level. Therefore, this novel coaxial nanoformulation may serve as a promising drug delivery platform for the treatment of bacterial infections including respiratory tract complications.

Antimicrobial activity of Plumbago indica and ligand screening of plumbagin against methicillin-resistant Staphylococcus aureus.

In this study, the antimicrobial properties of Plumbago indica root bark against bacterial strains and a fungal strain were investigatedusing the disc diffusion and minimum inhibitory concentration assays. Gas chromatography/mass spectrometry, nuclear magnetic resonance spectrometry, and column chromatography analyses were conducted to identify and isolate the active compounds. A docking study was performed to identify possible interactions between the active compound and DNA gyrase using the Schrödinger Glide docking program. Both methanol extract and the ethyl acetate fraction of the root bark showed significant antimicrobial activity against the gram-positive bacteria than against the gram-negative bacteria and the fungal strain. The active compound was identified as plumbagin. A disc diffusion assay of plumbagin revealed potent antimicrobial activity against methicillin-resistant Staphylococcus aureus. Molecular docking of plumbagin revealed high specificity towards the DNA gyrase binding site with a high fitness score and a minimum energy barrier of -7.651 kcal/mol. These findings indicate that P. indica exhibits significant antimicrobial activity, primarily due to the presence of plumbagin. The specificity of plumbagin toward DNA gyrase in S. aureus indicates the feasibility of utilizing P. indica for developing new drug leads against drug resistant microbial strain. Communicated by Ramaswamy H. Sarma.

Estimation of sex from the osteometric measurements of the femur in a contemporary Sri Lankan population / Estimación del sexo a partir de las medidas osteométricas del fémur en una población contemporánea de Sri Lanka

SUMMARY: Sex estimation from human skeletal remains is of vital importance in the buildup of a biological profile of an individual in medico-legal and bioarchaeological studies. The present study is focused on the estimation of sex from osteometric measurements of the complete femur and its fragmentary parts, and the development of a web based application related to this. Fifteen osteometric measurements were taken from 78 dry cadaveric femurs from the Faculty of Medicine, University of Kelaniya. Using R software, linear discriminant analysis and logistic regression methods were applied to build classification models with the help of the application of a stepwise procedure, to identify the best combination of measurements to estimate the sex of the femur. A cross-validation method was applied to estimate the predictive accuracy of each model. Since the linear discriminant analysis model gave more predictive accuracy than the regression model, we suggest using linear discriminant analysis to estimate the sex using osteometric measurements of the femur. From the whole femur measurements, a formula to determine sex was developed with highest total accuracy of 83 % using four parameters; epicondylar breadth, anteroposterior mid-shaft diameter, bi-trochanter length, and maximum shaft diameter. Similarly, measurements of transverse head diameter and bi-trochanter length with a total accuracy of 76 % for the proximal part of the femur, measurements of anteroposterior mid-shaft diameter with a total accuracy of 77 % for the mid-shaft, and measurements of epicondylar breadth and maximum length of the lateral condyle with a total accuracy of 70 % for the distal part of the femur were identified as significant discriminants to determine sex, and formulae were written accordingly. Average accuracy ranged from 83 % to 70 %, with male accuracy slightly higher than that of females. A web application to estimate the sex of femur using these formulae was developed and this will be of great importance for forensic medicine and bio-archaeological research in Sri Lanka.

RESUMEN: La estimación del sexo a partir de restos óseos humanos en los estudios médico-legales y bioarqueológicos es de vital importancia en la construcción de un perfil biológico de un individuo. El objetivo de este estudio fue la estimación del sexo a partir de medidas osteométricas del fémur completo y sus partes fragmentarias, y el desarrollo de una aplicación web relacionada con esto. Se tomaron quince medidas osteométricas de 78 fémures cadavéricos secos de la Facultad de Medicina de la Universidad de Kelaniya. Utilizando el software R, se aplicaron métodos de análisis discriminante lineal y regresión logística para construir modelos de clasificación con la aplicación de un procedimiento por pasos, para identificar la mejor combinación de medidas y estimar el sexo a partir del fémur. Se aplicó un método de validación cruzada para estimar la precisión predictiva de cada modelo. Dado que el modelo de análisis discriminante lineal proporcionó una mayor precisión predictiva que el modelo de regresión, sugerimos su utilización para estimar el sexo mediante mediciones osteométricas del fémur. A partir de las mediciones del fémur completo, se desarrolló una fórmula para determinar el sexo con la mayor precisión total del 83 % utilizando cuatro parámetros; anchura del epicóndilo, diámetro anteroposterior del tercio medio de la diáfisis, longitud bitrocánter y diámetro máximo de la diáfisis. De manera similar, utilizamos las mediciones del diámetro transversal de la cabeza del fémur y la longitud del bitrocánter con una precisión del 76 % para la parte proximal del hueso, las mediciones del diámetro anteroposterior del tercio medio de la diáfisis se obtuvo con una precisión del 77 %. El ancho del epicóndilo y la longitud máxima del cóndilo lateral con una precisión del 70 % para la parte distal del fémur se identificaron como discriminantes significativos para determinar el sexo y se escribieron fórmulas. La precisión promedio osciló entre el 83 % y el 70 %, siendo la precisión en los hombres ligeramente superior al de las mujeres. Se desarrolló una aplicación web para estimar el sexo del fémur utilizando estas fórmulas y creemos será importante para la medicina forense y la investigación bioarqueológica en Sri Lanka.

Use of intravenous N-acetylcysteine in acute severe hepatitis due to severe dengue infection: a case series.

BACKGROUND: Dengue fever is a common mosquito borne viral infection. Severe dengue fever associated severe hepatitis carries high mortality. Based on the beneficial effect of N-acetylcysteine (NAC) in paracetamol poisoning and non-acetaminophen induced liver failure, it is used in dengue fever associated hepatitis in clinical practice. We aim to study the reversal of liver enzymes with NAC in the setting of severe hepatitis due to severe dengue infection. METHODS: A retrospective analysis was conducted on hospitalized 30 adults with severe dengue fever with severe hepatitis. These 30 patients had aspartate transaminase (AST) and alanine transaminases (ALT) more than 500 U/L and/or PT INR (prothrombin time and international normalized ratio) more than 1.5. They were treated with NAC infusion of 100 mg/h for 3 to 5 days. RESULTS: The mean age of the group was 49.9 ± 11.46 years and 18 (60%) patients were males. Nineteen patients (63%) developed dengue shock. Of them 12 patients (40%) developed hepatic encephalopathy. Median AST on the day of administration of NAC was 1125 U/L interquartile range (IQR) 1653.25 while median ALT was 752 (IQR 459.25). There was a statistically significant reduction of both ALT (p = 0.034) and AST (p = 0.049) from day 1 to 4 after NAC infusion. Rise of platelet count between day 1 and day 4 also showed statistically significant difference (p = 0.011) but the reduction of prothrombin time and international normalized ratio (PT/INR) from 1 to day 4 did not show statistical significance difference. Mean duration of treatment with NAC was 3.61 ± 0.75 days while mean length of hospital stay was 6.2 ± 1.27 days. Only one patient died (3.3%). None of the patients reported adverse drug reaction due to NAC. CONCLUSION: Majority of patients demonstrated marked clinical and biochemical improvements and they recovered fully. We observed faster and significant recovery of liver enzymes following administration of NAC. Based on the above findings, this study provides preliminary evidence for the beneficial effect of NAC in severe hepatitis in dengue infection with greater survival benefits.

Periodic nanostructures: preparation, properties and applications.

Periodic nanostructures, a group of nanomaterials consisting of single or multiple nano units/components periodically arranged into ordered patterns (e.g., vertical and lateral superlattices), have attracted tremendous attention in recent years due to their extraordinary physical and chemical properties that offer a huge potential for a multitude of applications in energy conversion, electronic and optoelectronic applications. Recent advances in the preparation strategies of periodic nanostructures, including self-assembly, epitaxy, and exfoliation, have paved the way to rationally modulate their ferroelectricity, superconductivity, band gap and many other physical and chemical properties. For example, the recent discovery of superconductivity observed in "magic-angle" graphene superlattices has sparked intensive studies in new ways, creating superlattices in twisted 2D materials. Recent development in the various state-of-the-art preparations of periodic nanostructures has created many new ideas and findings, warranting a timely review. In this review, we discuss the current advances of periodic nanostructures, including their preparation strategies, property modulations and various applications.

Group B Streptococcus colonisation and their antimicrobial susceptibility among pregnant women attending antenatal clinics in tertiary care hospitals in the Western Province of Sri Lanka.

The proportion of Group B Streptococcus (GBS) colonisation in pregnant women >35 weeks of gestation was 18% and 49% by culture and real-time PCR respectively in selected hospitals from the Western Province of Sri Lanka. A Descriptive cross-sectional study was conducted from January to April 2019. Two low vaginal and rectal swabs were collected from 100 pregnant women. Identification of GBS was done by culture and real-time PCR. GBS isolates were found to be sensitive to penicillin, ampicillin, cefotaxime, vancomycin, while 5 and 4 isolates out of 18 were resistant to erythromycin and clindamycin, respectively. Further, there was a significant association between GBS colonisation and a history of vaginal discharge and unemployment.IMPACT STATEMENTWhat is already known on this subject? Prevalence of GBS colonisation in the vagina and rectum of pregnant women in developing countries ranges from 8.5% to 22%. The Conventional method of culture has been considered the gold standard for diagnosis, however, the culture method does not give positive results for all cases of GBS. Polymerase chain reaction (PCR) has been found to be more sensitive for the detection of GBS than culture. In Sri Lanka, ante-natal screening for GBS is not practiced as the prevalence of GBS is still unlcear due to non-availably of data. Only a few scattered studies have been conducted using culture in Sri Lanka. Thus there is an urgent need to determine the magnitude of the GBS colonisers of ante-natal women in order to set up guidelines for screening and management of GBS.What do the results of this study add? In this study, the overall GBS colonisation rate which was detected using both culture and PCR was 50% in Western Province of Sri Lanka. That was a high figure when compared to the figures which were detected previously in Sri Lanka using only conventional culture methods. The risk factors for GBS colonisation were found to have a significant relationship with the history of abnormal vaginal discharge. Further, it was found that when Candida species coexisted with GBS, the existence of GBS was enhanced. Penicillin remains the antibiotic of choice for GBS.What are the implications of these findings for clinical practice and/or further research? This study emphasises the importance of establishing national policies for screening of pregnant women of >35 weeks of gestation to reduce the risk of neonatal infection. Further, it gives an insight into the options of antibiotics that can be used for treatment of these GBS colonisers from Sri Lanka.

Detection and quantification of Aflatoxin B1 in corn and corn-grown soils in the district of Anuradhapura, Sri Lanka.

Aflatoxin B1 contamination adversely affects human health by impairing long-term physical and cognitive development. Several crops have been associated with aflatoxin B1 contamination and corn is one of them. In the Anuradhapura district of the North Central Province of Sri Lanka, corn is one of the main agricultural produce. Due to poor farming practices in this area, it is possible that aflatoxin B1 is somehow transported from soil to the corn ears. This study was carried out to detect and quantify aflatoxin B1 in corn and corn-grown soils in Anuradhapura. Corn (n = 60) and corn-grown soil (n = 60) samples were randomly collected from 20 minor-scale corn-grown fields with three random replicates. Each sample was prepared for the measurement of aflatoxin B1 levels using the Enzyme-Linked Immunosorbent Assay (ELISA). Though 20 ppb is considered as the poisonous or deleterious level for corn consumption, there were toxin contaminations of up to 60-70 ppb in the corn kernel, while majority of soil had 350-400 ppb of aflatoxin B1 levels. Fifteen corn samples had exceeded the acceptable level while 22 samples were free of aflatoxin B1 and 23 samples were within the acceptable level. The results showed that the presence of aflatoxin B1 in corn is not habitually distributed throughout Anuradhapura district and it increased with the soil aflatoxin B1 concentration. It appears that there is a relationship between corn kernel and corn-grown soil aflatoxin B1 levels.

Commercial Formulation of Chlorpyrifos Alters Neurological Behaviors and Fertility.

Pesticides are known to result in toxic insult. We aimed to evaluate Judo 40, the commercial formulation of chlorpyrifos on the neurological activities, fertility, and hormone levels of male rats. Male Wistar rats were treated orally with 1 mL of 20 or 50 mg/kg Judo 40. The doses were administered four times, twice a day. Sexual and exploratory behavior indices, fertility indices, serum androgen levels, blood acetylcholinesterase (BChE) levels, and neurological and muscular effects were evaluated. Serum testosterone and luteinizing hormone were significantly reduced in the rats receiving 50 mg/kg Judo 40. A reduction in viable implantation sites and live pups born were evident in the female rats mated with the male rats treated with the highest dose. Similarly, in the rats treated with the highest dose of Judo 40, a significant reduction in plasma BChE enzyme was observed. According to the results, prolonged Judo 40 exposure can cause impairment of the neurological alterations and sex hormones leading to impaired fertility. Therefore, chemical handlers should be educated on protection and risk minimization.

Rational Synthesis of Metallo-Cations Toward Redox- and Alkaline-Stable Metallo-Polyelectrolytes.

Cations are crucial components in emerging functional polyelectrolytes for a myriad of applications. Rapid development in this area necessitates the exploration of new cations with advanced properties. Herein we describe a combination of computational and experimental design of cobaltocene metallo-cations that have distinct electronic and redox properties. One of the direct outcomes on the first synthesis of a complete set of cation derivatives is to discover highly stable cations, which are further integrated to construct metallo-polyelectrolytes as anion-exchange membranes in solid-state alkaline fuel cells. The device performance of these polyelectrolytes under highly basic and oxidative environments is competitive with many organo-polyelectrolytes.

UV-irradiation of self-assembled triphenylamines affords persistent and regenerable radicals.

UV-irradiation of assembled urea-tethered triphenylamine dimers results in the formation of persistent radicals, whereas radicals generated in solution are reactive and quickly degrade. In the solid-state, high quantities of radicals (approximately 1 in 150 molecules) are formed with a half-life of one week with no significant change in the single crystal X-ray diffraction. Remarkably, after decay, re-irradiation of the solid sample regenerates the radicals to their original concentration. The photophysics upon radical generation are also altered. Both the absorption and emission are significantly quenched without external oxidation likely due to the delocalization of the radicals within the crystals. The factors that influence radical stability and generation are correlated to the rigid supramolecular framework formed by the urea tether of the triphenylamine dimer. Electrochemical evidence demonstrates that these compounds can be oxidized in solution at 1.0 V vs. SCE to generate radical cations, whose EPR spectra were compared with spectra of the solid-state photogenerated radicals. Additionally, these compounds display changes in emission due to solvent effects from fluorescence to phosphorescence. Understanding how solid-state assembly alters the photophysical properties of triphenylamines could lead to further applications of these compounds for magnetic and conductive materials.

Akaganeite nanorices deposited muscovite mica surfaces as sunlight active green photocatalyst.

Thin films of akaganeite [FeO(OH)] nanorices deposited muscovite mica (ANPM) surfaces are synthesized using the facile urea assisted controlled self-assembly technique. The synthesized materials are characterized using scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy, atomic force microscopy, X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy and thermogravimetric analysis (TGA). The prepared nanorices on mica surfaces show average particle length and width of 200 and 50 nm, respectively. Synthesized material acts as an efficient photocatalyst under UV and sunlight conditions as demonstrated by the degradation of standard methylene blue (MB) solution. The MB degradation efficiencies of the catalyst under exposure to 180 min sunlight and UV are 89% and 87.5%, respectively, which shows that the catalyst is more highly active under sunlight than under UV light. Therefore, the synthesized material is a potential green photocatalyst in efficient treatment of industrial dye effluents under direct sunlight.

Selective N1-Acylation of Indazoles with Acid Anhydrides Using an Electrochemical Approach.

An electrochemical synthesis method for the selective N1-acylation of indazoles has been developed. This "anion pool" approach electrochemically reduces indazole molecules generating indazole anions and H2. Acid anhydrides are then introduced to the solution resulting in selective acylation of the N1-position of the indazoles. This procedure can also be applied to the acylation of benzimidazoles and indoles. The reaction can also be performed using a 9 V battery without loss of reaction efficiency.

Facile and low-cost synthesis of pure hematite (α-Fe2O3) nanoparticles from naturally occurring laterites and their superior adsorption capability towards acid-dyes.

Hematite nanoparticles have a broad range of outstanding applications such as in wastewater treatment, electrolytic studies, and photoelectrochemical and superparamagnetic applications. Therefore, the development of facile and novel methods to synthesize hematite nanoparticles using low-cost raw materials is an important and timely requirement. In this study, we have developed a facile economical route to synthesize hematite nanoparticles, directly from the naturally occurring material laterite. Laterite is a rock that is rich in Fe and Al with extensive distribution in large mineable quantities in many countries around the world, though not yet utilized for major industrial applications. In this method, ferric ions in the laterite were leached out using acid and the solution obtained was hydrolyzed with slow-release hydroxyl ions which were acquired by aqueous decomposition of urea. The resulted precursor was calcined to obtain hematite nanoparticles. Characterization data shows that the final product is comprised of spherical hematite nanoparticles with a narrow particle size vs. frequency distribution with an average particle diameter of 35 nm. The synthesized product has a purity of over 98%. Furthermore, the synthesized nanoparticles show an excellent adsorption percentage as high as 70%, even when the initial dye concentration in water is 5000 ppm and the amount of material is minimal, towards acid dyes which are excessively used in textile based industries. Such acid dyes are a threat to the environment when they are released into water bodies by industries in massive quantities. Therefore synthesized hematite nanoparticles are ideal to treat dye wastewater in industrial effluents because such nanoparticles are low cost and economical, and the synthesis procedure is rather facile and effective.

Structure-based exploration and exploitation of the S4 subsite of norovirus 3CL protease in the design of potent and permeable inhibitors.

Human noroviruses are the primary cause of epidemic and sporadic acute gastroenteritis. The worldwide high morbidity and mortality associated with norovirus infections, particularly among the elderly, immunocompromised patients and children, constitute a serious public health concern. There are currently no approved human vaccines or norovirus-specific small-molecule therapeutics or prophylactics. Norovirus 3CL protease has recently emerged as a potential therapeutic target for the development of anti-norovirus agents. We hypothesized that the S4 subsite of the enzyme may provide an effective means of designing potent and cell permeable inhibitors of the enzyme. We report herein the structure-guided exploration and exploitation of the S4 subsite of norovirus 3CL protease in the design and synthesis of effective inhibitors of the protease.

Spontaneous and strong multi-layer graphene n-doping on soda-lime glass and its application in graphene-semiconductor junctions.

Scalable and low-cost doping of graphene could improve technologies in a wide range of fields such as microelectronics, optoelectronics, and energy storage. While achieving strong p-doping is relatively straightforward, non-electrostatic approaches to n-dope graphene, such as chemical doping, have yielded electron densities of 9.5 × 10(12) e/cm(2) or below. Furthermore, chemical doping is susceptible to degradation and can adversely affect intrinsic graphene's properties. Here we demonstrate strong (1.33 × 10(13) e/cm(2)), robust, and spontaneous graphene n-doping on a soda-lime-glass substrate via surface-transfer doping from Na without any external chemical, high-temperature, or vacuum processes. Remarkably, the n-doping reaches 2.11 × 10(13) e/cm(2) when graphene is transferred onto a p-type copper indium gallium diselenide (CIGS) semiconductor that itself has been deposited onto soda-lime-glass, via surface-transfer doping from Na atoms that diffuse to the CIGS surface. Using this effect, we demonstrate an n-graphene/p-semiconductor Schottky junction with ideality factor of 1.21 and strong photo-response. The ability to achieve strong and persistent graphene n-doping on low-cost, industry-standard materials paves the way toward an entirely new class of graphene-based devices such as photodetectors, photovoltaics, sensors, batteries, and supercapacitors.

The effect of confinement on the crystalline microstructure of polymer : fullerene bulk heterojunctions.

We investigate the effect of confinement on the crystalline microstructure of the polymer component of polymer : fullerene bulk heterojunction thin films using grazing incidence wide angle X-ray scattering. We find that the polymer crystallite size decreases and the alignment of the molecules along the surface normal increases, as the thin-film thickness is reduced from 920 nm to <20 nm and approaches the thin-film confinement regime. Furthermore, we find that the polymer crystallite size near the surface (air interface) is lower than the crystallite size in the bulk or the bottom (substrate interface) of bulk heterojunction films thicker than the confinement regime. Variation in polymer crystallite size can cause changes in charge carrier mobility and recombination rates, which in turn affect the performance of bulk heterojunction thin film devices such as photovoltaics and photodetectors.